The main function of growth hormone (GH) is to promote linear growth during childhood; however, GH secretion persists throughout life after cessation of skeletal growth. This hormone has important physiological functions apart from growth stimulation. Many aspects of the physiological and pharmacological actions of GH have been recently clarified. Accordingly, in the last years, especially since the introduction of recombinant human GH (rhGH), GH therapeutical applications have increased. In the last years, the main clinical application of rhGH has been to stimulate growth of growth-retarded GH deficient (GHD) children. More recently, rhGH therapy has been approved for other conditions associated with short stature, including Turner syndrome and end stage renal disease. In adults, the only therapeutic indications approved are the adult GHD syndrome and the AIDS-associated wasting. This review outlines the present knowledge of the physiological effects, clinical applications, therapeutic perspectives, side effects, precautions and contraindications of rhGH therapy in adults.